Process of making fusible links



L. M. LEWIS.

PROCESS OF MAKING FUSIBLE LINKS.

APPUCATION FILED mu 6,1920.

1,382,368; Pfatanted June 21, $521.

fig. :2: a F f h I f e r 7, E19. 9, i m I 5 J4 .17

INVENTOR WITNESS ATTORNEYS y UNITED STATES ears N'l' QFFHCE.

LEROY M. LEWIS, OF PHILADELPHIA, PENNSYLVANIA.

PROCESS OF MAKING FUSIBLE LINKS.

To all whom it may concern:

Be it known that I, LEROY M. Lewis, a citizen of the United States, and a resident of the city of Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented certain new and useful linprovements in Processes of Making Fusible Links, of which the following is a specification, reference being made to the accompanying drawings, illustrating one mode of performing the process of my invention.

The invention relates to a process of making fusible links of the type disclosed in my copending applications for United States Letters Patent, Serial Numbers 292, r09 and 368,888, filed April 2 1, 1919, and March 26, 1920, respectively.

Among the objects of my invention is to form a link structure with elements which will properly be retained in the sprinkler head against premature operation andwhich will operate efficiently upon the fuslng of the fusible material between the elements thereof.

I have discovered, in making or forming plates for fusible links, that by first later ally offsetting a portion of each plate at the place finally shaped into laterally bent portions, between which a strain member may be located when the plates are assembled, and then pressing, wlth a properly formed die, against the offset portlon to return the same to the finished or deslred shape to form the laterally projecting socket portions of the plates, a greatly improved plate is produced. In previous methods of making these plates, the central port1 on of the plate was subjected to a Che action which, in effect, was a drawing action, the portion acted upon by the dies being drawn or stretched from the remainder of the plate to form a laterally extending socket portion, in which was located a strain element. This made the plate thin or weak at certain points, particularly at the lines where the edges of the strain member were seated, the weakened part having to receive the full force of the strain applied to the link. I have discovered that by reversing the dies and by first offsetting a central portion of a plate blank and then sub ecting the offset portion to compressing die action to return said offset portion to the desired form, the drawn and weakened portions are wholly avoided, and a strong, tough and accurately made plate is produced.

Specification of Letters Patent.

1920. Serial No. 379,253.

It is therefore an to provlde a process essential to indicated.

consisting of the steps produce the desired result above Another object of my invention is to carry out the steps of the process to effect greatly reducing processes heretoan economy of material, the waste incidental to the fore in use.

Such other advantages and objects as are present 1n my new and improved process wlll more fully appear in the following specification.

Referring to the drawings in which I illustrate the steps of the process that may be utilized in this invention,

Figures 1 and 2 are views respectively in elevation and plan of an end of a strip of metal from which the link plates may be made;

Figs. 3 and 1 are views respectively in elevation and plan of the same showing the steps of offsetting a portion;

Figs. 5 and 6 are similar views of the offset blank cut from the strip shown in Figs. 3 and 4:;

Figs. 7 and 8 respectively show sectional and plan views of a blank cutand pierced to the particular plate shape or configuration desired;

Figs. 9 and 10 are similar views of the finished plate showing the shape of the socket portion formed in the plate;

Fig. 11 is a view in section of the compressing dies and an offset blank prior to the die pressing action;

Fig. 12 is a similar view at the end of the die operation showing the finished shape of the socket portion in the plate;

Fig. 13 is a section, on an enlarged scale of a plate formed by the method hitherto in use and showing the points of weakness therein; and

Fig. 14 is a similar view of a plate formed in accordance with this invention and showin the strengthened parts thereof.

lieferring now more particularly to the drawing, in which the same reference characters are used to designate corresponding parts in the various views illustrated, in forming the plates a nite length may be fed from a suitable source into a two-station die press, (not shown), in the first station of which the strip 1 may be upset' or offset to produce Patented June 21, 1921.

object of my invention metal strip 1 of indefia substantially semicircular offset portion shown in Fig. 12, the

2 as clearly shown in Figs. 3 and a of the drawing, which is then fed to the second station of the press where the end of the strip may be cut off to form the blank 3 as shown in Figs. 5 and 6, such blank being provided with the offset portion 2 substantially at the center thereof. The type of die press used for this may be of any suitable construction, and its illustration here is deemed unnecessary. The blank3 may then be placed into another die press where the blank is suitably trimmed and pierced to produce the blank 4 of the contour illustrated in Figs. 7 and 8 of the drawing or other suitable contour, the central aper ture 5 being pierced through the offset portion 2 of a purpose hereinafter more fully described.

The blank 4 may then be transferred to the compression die press, which may be of the coin die press type, in which a male die 6 is placed in the lower die head 7 and a female die 8 is carried by the upper die head. The die 6 may be located in a socket 9 pro vided in the die head 7 and adapted to freely move vertically therein. The dies and the socket are preferably of the same contour as the plate 4. The die 6 may be suitably supported upon a plunger 10 adapted to freely move through the-aperture 11 provided in the lower portion of the head 7. The plunger 10. may be connected to any suitable part of the die press whereby the die 6 may be returned to its raised position after a die operation. Upwardly projecting portions or pilot pins 12 and 13 may be provided on the die 6 to register witlrthe sockets 12 and 13' of the die 8 whereby the two dies and the plate a may be maintained in proper relation as the parts approach each other, the projections also serving to prevent lateral crawl of the plate during the operation of the dies.

In operation, the blank 4 is placed upon the die 6 with the projections 12 and 13 extending upwardly through the apertures 14 and 5 of the plate 4i and with the offset portion 2 extending upwardly and located over the die surface 15 of the lower die 6, the portion 16 of the head being guided in the notch 17 of the plate 4, as the latter is caused to descend. It will be observed that the side walls of the socket 9 are slightly inclined from the vertical to converge downwardly whereby, as the plate 4: is forced downwardly within the die 6, the'edges of the plate .4 will be slightly compressed so that as the plate is lowered to the position plate will be slightly smaller in contour or area. When the plunger 10 moves upwardly with the die 6 from the position shown in Fig. 12 to that shown in Fig. 11, the plate 4 will not bind in the socket 9 and may be readily removed either by hand or by any suitable means provided causing it to flow or be pressed into the form shown, on an enlarged scale, in Fig. 14: so"

that the angles or recesses in the die surfaces will be completely filled with the metal of the offset portion 2. The resultant socket portions 19 thus formed in the plates are of uniform thickness, tough, strong and correctly shaped to efficiently retain, with greater tension capacity, the strain element or the key located in the socket formed between such portions in the assembled link. It will be observed that the material or web between the socket portion 19 and the adj acent portion 20 of the plate is not drawn out plates.

In the old process the dies are located in reverse relation and as the projection of the male die is forced against the plate 21-(see Fig. 13), the portion 22 of the plate is formed by adrawing action causing anarrowing or constricture 28 betweenthe portion 22 and the portion 21 of the plate. The web portion 23 thus formed is weak and provides a poor shoulder against which the edge of the strain member must bear when the link is assembled and placed under pressure. In addition to the above, such plate also has another constricted and weakened portion 24, similarly formed.

In my device the offset portion 2 is formed without any drawing action or stretching of the strip 1, the strip 1 being fed forward during the lateral up-setting or offsetting of the portion 2 suiiiciently'to compensate for the same. Then, by subjecting this offset portion to compressing die actions the same will becaused to flow back intothe final form of socket portion desired, as isassembly. In the old form of key, thefcorner 27 is rounded due to the drawing action of the (1163, and the strain member or key will not rest squarely upon the portion 23 but is constantly urged'to move over the and weakened as in the old form oflatter, it will be observed, will re rounded portion 27 tending to wedge the 7 plates apart, a condition that is obviously undesirable and which often causes prema-' ture operation of the link structure. r

I have found, by my new process of making link plates, an economy in material is secured,'that the plates are tougher, more -accurately formed and capable of more efficiently retaining the strain member. Inasmuch as the tension capacity is greater, the angle of the socket portions need not be as great as in the prior forms and a thinner link may thus be produced withthe line of strain nearer to the central plane of the assembly.

While I have herein shown one mode of carrying out my invention, it is to be understood, however, that the latter is not limited to the particular steps or operations herein described and illustrated on the accompanying drawings, but that other modes are comprehended thereby without departing from the spirit of the invention and the scope of the appended claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent of the United States is:

1. The process of making a plate for a fusible link which comprises the steps of forming a transversely extending offset 1 n a metal blank, palcing the blank in a die press and compressing said offset portion to form a flat portion angularly disposed relative to the body portion of the finished plate and connected thereto by a web of thickness substantially equal to that of said body portion.

2. The process of making a plate for a fusible link which comprises the steps of forming a curved transversely extending offset in a blank, placing the blank in a dle press comprising male and female dies and compressing said blank into conformity with the shape of said dies, whereby sa1d offset portion is transformed to a flat portion angularly disposed with respect to the body of the plate and connected thereto by a web of thickness substantially equal to the body portion.

3. The process of forming a plate for a fusible link which comprises the steps of forming in a metal blank a transversely extending offset with the metal in the offset portion of substantially the thickness of the metal of the blank, placing said blank m a die press comprising male and female dies and compressing said blank by causing said dies to approach each other, whereby said offset is transformed to twonormally positioned integral. portions each connected with the body of the blank and angularly disposed with respect thereto.

4. The process of making a plate for a fusible link which comprises the steps of laterally dishing a flat blank to form a curved offset thereon of substantially the same thickness as the body of the blank, placing the blank with said offset projectlng upwardly upon the upper face of the male member of a die and compressing the blank against said member by moving the femalegularly disposed with respegt to the body,

portion of the finished plate and connected thereto by a web of thickness substantially equal to said body portion.

5. The process of making a plate for a fusible link which comprises the steps of laterally offsetting a strip of flat stock to form a substantially semi-circular offset of substantially the same thickness as the body of the strip, severing a blank including the offset from the strip, placing the blank upon the male member of a die having an upwardly projecting portion with said offset over said upwardly projecting portion, and compressing the blank against said member by moving the female member of the die downwardly against the blank, whereby the blank is caused to assume the shape of the dies and the offset portion is transformed to a flat portion angularly disposed with respect to the body portion of the finished plate and connected thereto by a web of thickness substantially equal to said body portion.

6. The process of making a plate for a fusible link which comprises the steps of laterally offsetting a strip of flat stock to form a substantially semi-circular offset of substantially the same thickness as the body of the strip, severing a blank including said offset from the strip, placing the blank with said oflset extending upwardly upon the male member of a die conformable to the contour of one side of the finished plate and having an .upwardly projecting portion adapted to enter said offset and compressing the blank against said male member by bringing the female member of the die which is conformable to the other side of the finished plate against the upper surface of the blank, whereby the metal in the offset of the blank is caused to flow to assume the shape of the adjacent portion of the dies and is transformed to two normally positioned portions each connected with the body of the blank and angularly disposed with respect thereto.

7. The process of making a plate for a fusible link which comprises the steps of laterally offsetting a strip of flat stock to form a substantially semi-circular offset of metal of substantially the same thickness as the body of the strip, severing a blank including the offset from the strip, cutting and piercing the blank to desired shape, placing the blank, with the open side of the offset downward upon the male member of a die having an upwardl projecting portion adapted to enter the 0 set and then compressing the blank against said male member by first bringing the female member of the formed in two integral normally disposed die against the upper surface of the offset webs forming a V-shaped offset in the finprior to contact of the other portions of the ished plate integral with the' body portion 10 member with the rest of the upper surface of thereof and in angular relation therewith.

5 the blank, whereby the metal in the offset In witness whereof, I have hereunto set portion of the blank is caused to flow to asmy hand this 30th day of April, 1920.

' sume the shape of the dies and is trans-- LEROY M. LEWIS. 

